Jorge Lorenzo, at the end of the Catalan Grand Prix: “At the start I had a good start and, with the new tires, I was more or less on the same level as the other drivers. But as I knew before the race, if I started to have graining on the front tire, I would struggle. That's what happened.
With the same bike, Rossi didn't have as much graining. It seems he drives differently than me and can save the front tire more normally. It is also very good in difficult conditions, when there is no grip.”
Graining, graining… A term all in all rather less used in motorcycles than in F1, but which nevertheless characterizes a very real phenomenon which appears when the tire is not really in line with the grip of the track.
In a “chronological-logical” approach, we therefore first questioned Randy de Puniet on the consequences of graining on pilotingthen Guy Coulon to have “the point of view from the box”, and, in a final part, we obtained the expertise of Michelin On the question.
Nicolas Goubert, Deputy Director, Technical Director and MotoGP Program Supervisor at Michelin Motorsport : “Graining is an English word that is used differently in the world of cars and in that of motorcycles. In the car, it's used a lot but it doesn't have the same meaning at all and, moreover, I'm not convinced that all the people who use it in MotoGP all give it the same meaning (laughs).
In cars, it is used when the rubbers are not working within their operating window, often when temperatures are too low and the tire wears prematurely. Usually it happens in the morning when it's cool and it doesn't happen in the afternoon. The tire then wears “in rolls”.
Concerning Lorenzo, who actually used this word, he uses this term when the tire marks itself over the laps. And in Barcelona, it happened to him quite quickly. But a pilot may or may not feel it. According to him, it was associated with a drop in potential, and when the driver is somehow afraid of that, in fact, he is immediately afraid of falling as soon as he sees the tire mark a little, even if the potential has not necessarily decreased.
But in Barcelona, Lorenzo looked genuinely embarrassed in the race, much more than his teammate. And it happened much faster on his bike than on Rossi's. »
Is it due to the piloting?
“Yes, probably, to the whole piloting and settings. There was a big gap between the two. It is sometimes difficult to understand and find the solution. There, we did not have, as in a car, wear in rolls, but just a deterioration in the appearance of the tire following rapid and localized wear.
At Lorenzo, it was a fairly narrow strip that appeared after a few laps, with a tire marking a width of one centimeter, no more. It was the result of the driver-settings-tire combination and it happened much later to Rossi who declared that he had been satisfied with the front tire until the end of the race.
So even if we saw that the tire had worked and was marked, sometimes there is no impact on the level of grip. It happened later with Rossi, and he wasn't embarrassed, whereas with Lorenzo, it happened much earlier, and he was embarrassed.
However, we can notice that Lorenzo was extremely efficient on Friday, although he already had what he calls this graining. On Saturday and Sunday, he performed less well. Was it also due to the route which suited him less well, was it marked more than others by the fatal accident that we experienced, Luis Salom being Majorcan, I don't know. »
